I ´ve been using the Konnekt 24D for four months now. It´s hooked up via firewire to my Dell Inspirion 6400 (dual core) laptop as "exclusive" DAW.
I must add that Dell is not the most stable PC for home recording, but not in my case. Because its exclusive for audio for me with only XP-SP2 and fine tuned for audio recording, so no problems for me there. Sometimes its a matter of "how and what" you have set-up on your PC. It works fine with Cubase SX3.03, Reason 2.5 and EZDrummer.
The Konnekt 24D sounds very very good, and the converters are awsome to my ears. Fabrik C and R are great sounding DSP plugg-ins, In fact if you bought them alone, they would cost you as much as the K24D.
I know the K24D is new to the market, and yes there is some issues with Intel based Macs, but its not the only Interface that has issues with Intel based Macs lately.
T.C is working hard to fix its bugs and has had three driver updates since it came out, with a mayor update due after this months NAMM show with some extras added, so stay tuned.
All I can say is that my Konnekt 24D works great in my set-up since day one. I would not post this if I had problems with it. Like anybody, I dont like to have problems with my gear, so please dont think I wanna sell you something. I´am even thinking of getting the Konnekt 8 to hook-up via firewire chain to have extra pres. I´am very happy with it

Just my 0.20€ on the subject.
Good care and good luck in your quest.